Jenn air refridgerator model 2089HEP, less than one month old, top section will not cool below 60 degrees although freezer seems okay. Any ideas? Any ideas with the warrenty versus a return?

Use the link below to view and read the user manual. If this is a used refrigerator it is possible that there may be a problem but it should be minor. The refrigerator section is cooled by air from the freezer. This problem is usually caused be excessive frost but you should not have frost buildup in only 24 hours.
There is also parts lists and diagrams.on the site.
I am also including a link to youtube videos about refrigerator problems.
FGHT1832PF0 FRIGIDAIRE REFRIGERATOR Manual

Frigidaire FGHT1832PF freezer cold refrigerator warm YouTube

Possible that the vent is getting blocked to prevent the cool air to be blown into the fridge section. So make sure that the auto defrost is working, if not check the auto defrost timer section, the fan, the heaters.
make sure that the thermostat is set to normal.
Finally shut off the fridge for 6-8 hours and see if the cooling resumes. If so the defrost section must be revisited

I had same issue this past week. Refrigerator up to 45 freezer up to 15. Ice would melt and then everything would get cold again. Ice formed on everything. Next thing you know it was warming up again. I knew the rubber seal on door flap that opens to let ice out warped during summer months because I keep it 78 in summer. Had that replaced today. Temperatures have gone back to normal and stayed ALL DAY (knock on wood). Check door flap seal sticking your hand up making sure you don't push in the water tab. You should be able to feel if it is warped/wavy like an old LP or not. Good Luck.

turn freezer to higher temp and turn fresh to lower temp this maximizes airflow into the refrigerator. check the door that regulates airflow into fresh side..see if its stuck closed for some reason. good luck! :)

Problem seems to be solved. I unplugged it for a short time and plugged it back in. I'm guessing it needed to be re-set.

Check the fan located in the freezer compartment.

This fan blows the cold air from the freezer into the fridge and is about 40 dollars for the part. Simple to fix too.

Gary

We are not sure what precipitated the temperature swing up; however, within about an hour of emptying quite a lot of foodstuffs from top and bottom sections of the unit, I felt the cold air start to flow out of the rear vent. Within two hours, the upper section had dropped to about 50 degrees and by the next morning to 36. The freezer seemed to recoved on its own too, having risen to almost 8 degrees and then recovering to 0. Just patience and a smaller food payload?

Good idea to call a service tech. If it is a compressor problem it should be covered by warranty. If there is frost on the back wall of the freezer section you have a defrost problem. This would not be covered by warranty. If you have a compressor problem it usually is indicated by a hum and then a click from the back of the refrigerator near the bottom.

If the fan is running you more than likely have a defrost problem.
Look at the back wall of the freezer section if it is frosted up. it's not defrosting. This keeps the air from circulating through the refrigerator section.

fridge takes its coldnest from the freezer check if the fan is running or if the vent is close